[0011]The above problem is solved by an operating mechanism for a parking brake, particularly for motor vehicles, which is arranged in a housing. This operating mechanism comprises a threaded rod driven by a motor having a first brake cable fixing guided on said threaded rod for the transformation of the rotation of said motor in a linear movement of said brake cable fixing and a second brake cable fixing in axial arrangement with said first brake cable fixing and said motor for performing a relative movement of said first and said second brake cable fixing to each other wherein said first and said second brake cable fixing can execute a common relative movement in view of said housing for a uniform load distribution to the connected brake cables.
[0012]The operating mechanism for a parking brake provided by the present invention is qualified by its constructive simplicity which is obvious by means of the limited number of single components. In the present invention, a motor drives a threaded rod without using a set of gears. On the thread of said threaded rod, a brake cable fixing is guided which is screwed on said threaded rod or from said threaded rod by means of a rotation of said motor. In this manner, a rotation of said motor is transformed in a linear movement of the brake cable fixing and, thus, the brake cables. Furthermore, a space saving arrangement of said operating mechanism follows since the first and the second brake cable fixing as well as the motor are positioned in an axial arrangement. In case of a transmitted rotation, both brake cable fixings carry out a relative movement to each other whereby a mechanical loading is transmitted to the brake cables or the same are released. The first and the second brake cable fixing are linear or curve linear displaceably arranged so that they can carry out a common relative movement with respect to the housing. In this manner, the mechanical loads generated by the operating mechanism are uniformly distributed to the connected brake cables. The above arrangement provides besides a space saving operating mechanism for a parking brake a lighter construction compared to the prior art as well as an arrangement requiring lower manufacturing and maintenance efforts.
[0014]In the arrangement of both brake cable fixings on the threaded rod, the first brake cable fixing is displaceably guided on the thread of said threaded rod. The second brake cable fixing is not directly displaced by means of the rotation. This arrangement comprising three parts guarantees a simple displacement of the brake cables as well as a simply producible mechanism requiring low maintenance efforts. The threaded rod with said two brake cable fixings is axially displaceably arranged in spite of the rotation transmission for the motor to said threaded rod. Thereby, mechanical loads are uniformly distributed to the connected brake cables. The connection between said motor and said threaded rod is thus qualified by a rotation transmission while a translational motion in axial direction of said motor in said threaded rod is allowed.
[0020]Further preferably according to the invention, said motor on which said second brake cable fixing is arranged as well as said threaded rod coupled thereon are displaceably arranged in axial direction of said threaded rod. During a rotation of said threaded rod, thus, said motor with second brake cable fixing is moved in a direction of said first brake cable fixing. In this manner, the brake cables are tightened. By the displaceable arrangement of said motor with said second brake cable fixing and said threaded rod with said first brake cable fixing, a uniform load distribution to the connected brake cables is guaranteed. Therefore, the whole assembly comprised of said motor with the second brake cable fixing and the threaded rod with said first brake cable fixing is displaced within the housing of the operating mechanism. Thereby, a space saving and constructively simple assembly of an operating mechanism for a parking brake is provided.
[0021]According to a further preferred embodiment of the present invention, the first brake cable fixing and the second brake cable fixing with said motor are displaceably guided in track-like recesses of said housing whereby their rotation is prevented.
[0028]The transmission of the rotation of said motor by means of the coupling element to said threaded rod realizes a space saving and a weight saving construction of said operating mechanism. Additionally, the present invention shows that a gear assembly related to high production costs and high maintenance efforts is dispensable for an effective operating mechanism of a parking brake.